The present invention relates to the adjustment of flaps, particularly high lift flaps, as provided on and for wings of aircraft.
More particularly, the invention relates to the adjustment of such flaps or flap systems arranged along the trailing edge of the wing, under utilization of carrier and boom arms, levers, linkages, drives, gears, transmission devices, pivotable devices, as well as devices for receiving and holding flaps, as well as the flap adjusting structure.
Flaps, or flap systems, are used on the wings of aircraft for the control of the lift, and here particularly for lowering the minimum speed during landing. The flaps will be protracted from a retracted position under utilization of a suitable kinematically operating mechanics, for purposes of increasing the effective lift area. In the retracted position, the flaps are, in fact, as far as the wing's contour is concerned, a part of that wing contour and will be as unobtrusive as possible, particularly as far as that erodynamically configured contour is concerned. The flaps of the system are simultaneously or separately moved in that they are caused to run along a curved path, and down to thereby increase the circulation of air flow around the wing.
Known devices for flap adjustment are configured to have, in fact, a curved track as seen in the direction of the chord depth of the wing. These tracks may include guide rails which are protracted or retracted, and held in certain carriage or slide structures carrying the flaps, while moving on these rails. In addition to crosswise retraction and protraction, the flaps permit pivoting on axes parallel to the span of the wing. Other known devices for flap adjustment include carrier arms; the high lift flaps are mounted on these carrier arms. Together, carrier arms and flaps can be protracted and pivoted down, under utilization of a particular track, and vis-a-vis the remainder of the wing.
In order to obtain flap pivot radii, which at one end permit a predictable flow pattern, that is a favorably flow pattern in all pivot positions and in relation to the wing, and which, on the other hand, permit a highly effective lift increase area, the carrier arms for the flaps will have to have fairly long length extensions. This then poses a problem in that the carriers, once retracted, cannot completely be accommodated within the aerodynamic contour of the wing. Rather, these carriers may project from the underside of the wing. This, of course, entails certain drag, and to minimize the drag, one needs to have a cover for the projecting carrier arms portions.
Lever linkages for pivoting such flaps are known which do, in fact, lie inside the contour of the wing when retracted. But these linkages and transmissions are quite extensive and complicated, and, in fact, it was found that owing to the space requirements, this kind of an arrangement can be used only when the wing is relatively thick.